But in your example above, the person autopays their bills with fiat and then converts the remainder in bitcoin. They transact in fiay and then save in bitcoin, and probably spend and replace in bitcoin. I agree with 95% of your example, except being on a bitcoin standard already part.
Discussion
It is possible to use more than one currency, but be on the standard of only one. I use USD, Bitcoin and Euro, for instance. If I convert from one to the other, or send or receive payments from "foreign" currencies, that doesn't change the underlying standard.
I am on the Euro standard in Germany and the USD standard when in the US (I have a bank account there), but am slowly transitioning to the Bitcoin Standard.
Zaps have given me some affinity for satoshis, as my base zap amount is always equal to roughly 2¢ in Euros.
27 sats ≈ 2¢
2700 sats ≈ €2
27000 ≈ €20
this is what unit of account means, it's a well known concept in accounting of international trade for decades
i also treat bitcoin as my unit of account and sats as my cents
Yes, and I will consider the Euro 💶 pointless paper, once we reach 1 sat = 1¢
That's why I made the diagram. Countdown to irrelevance.

i think by that time a lot of people will have the same opinion
i think that the naysayers and the bitcoiners both are wrong about how fast this happens, i'm very familiar with the physics of state changes from chemistry, chaos theory and computer science i will say that in a matter of weeks, at best, the world will turn against fiat currency